It gets stuck when the drive doesn't exist

Let's say I have some job that copies from, say, C to D. If D doesn't exist, instead of stopping it just keeps trying in vain. When you click cancel, it pauses (hey!) instead of cancelling. So one has to resort to killing the process from Task Manager.

It should stop trying if it sees there's no such drive (I assume it applies for both the source and the target).